@Trumpetier to answer your original question, from your first post you obviously know quite a lot about fishing already and as you said you know your way around a rod. My suggestion to you to get a decent used rod and not a starter kit comes from this and I see
@guzzicat has also suggested the same.
Starter kits are great for someone just starting out fishing and they are not sure if they'll like it, but I would suggest that an experienced fisherman who will soon want to progress, for me, they are restrictive. I've tried several including my next door neighbours Orvis kit which is supposed to be a fast action rod but found it just a tad sloppy and the line like something one should use for drying washing and certainly not like one of their better rods. Cheap kits tend to be made to a price.
Also, if you find yourself not using it as much as you'd like, a good rod bought at the right price will sell again easily for roughly what you paid for it.
The trout season has finished now so you've got until March to buy something, although Grayling are still available until March and of course you can still fish most lakes for trout if you wish.
As a good all rounder for river and lakes a 9' 5 weight will suffice with a weight forward #5 line. Although a 5 weight won't cast a massive Zonker lure as easily as say a #7, it will present a dry fly well and cast most nymphs a small lures well.
I'm sure you are aware, a fly rod casts the line whereas course and sea rods cast weights, lures or floats. I would suggest a fast action rod for someone who knows their way around a rod, this will eventually give you good distance and great presentation and better casting in windy conditions. Again, as you may know when you watched Mortimer and Whitehouse, with fly fishing you will make many more casts than course of sea rods. Consequently a light #5 can be used all day without giving you tennis elbow.
I would also suggest you study a little entomology via YouTube or Google, you don't need to become an expert over night but understanding when to use which type of fly will help. This can be a minefield but for now I'll leave it at that.
Certainly looking at Lee71's collection it'll help to recognise the Buzzers, Emergers, Zulu's, Damsel Nymphs, Ants, Bloodworms etc in his boxes and when to use them.
I looked to see if there are any fishing shops in Middlesbrough and found Keiths Sports in Saltburn which you may know as he sells guns as well. Might be worth paying a visit to see if you can try a rod or two.